What Happens?

Software and cathedrals are much the same; first, we build them, then we pray. What happens when you type https://www.google.com in your browser and press Enter.

To answer this question,

1. https:// is a scheme, it is a Secure Hypertext Transfer Protocol.
2. www is a subdomain to google.com domain, it works like an identifier or an address to the website that points to a specific server IP address serving the website.

When a user types in the URL and presses enter, the browser first needs to figure out the IP address of the server hosting the website. It does this by performing a DNS query (also known as DNS request) where the user's computer (DNS client) asks for the IP address associated with the domain name from a DNS server (a computer server that contains a database of public IP addresses and their associated hostnames.)

The Protocol Suite: TCP/IP

With the IP address at hand, Transmission Control Protocol/Internet Protocol (TCP/IP) - the protocol suite - kicks in. TCP establishes a reliable connection between your machine and Google's server, ensuring data integrity and order. IP, on the other hand, is responsible for routing the data packets to the correct destination.

HTTPS/SSL

TCP/IP connection has been done, the browser proceeds to communicate with the server using a secure protocol, Hypertext Transfer Protocol Secure (HTTPS). This protocol defines different types of requests (eg; GET, POST and PUT) and responses that are secured by a standard security protocol called Secure Sockets Layer (SSL) which encrypts and decrypts the data from the client to the server infrastructure at the load balancer.

Load Balancer

Arriving at Google's premises, a load balancer warmly welcomes the packets. Its job is to distribute incoming network traffic across several servers to ensure no single server becomes overwhelmed with too much traffic. This way, it ensures a seamless user experience.

The Great Wall

Before the packets venture further, they encounter the firewall - a security system ensuring that only safe and authorized traffic is allowed through. The firewall scrutinizes the packets based on predefined rules before permitting them onward.

Web and Application Server

Let’s recap, the user types the URL from the browser and types enter, then the browser figures out the IP address of the domain name by performing a DNS lookup. Once the IP is found the browser initiates a TCP/IP connection, then the request is analyzed by the firewall, and then gets to the load balancer that distributes it to a web server. A web server is software and hardware that only handles HTTP/HTTPS requests and servers static content like simple HTML pages, plain text files, or images.

An Application server runs behind a web server and in front of a Database Management System (DBMS). Its main purpose is to generate dynamic content supporting an application’s development and delivery providing business logic behind the application.

Data Management

Above we mentioned the ****Database Management System (DBMS); it is a program that allows the interaction with a database (an organized collection of structured information, or data stored in a computer system) to define, manipulate, retrieve and manage the data according to the request. The Database in this context will serve the user any information he is querying from google.com and store any information like account creation.

Once the request has been processed the webserver responds back to the user/client and that’s what happens when you type https://www.google.com in your browser and press Enter.